A prior art gas flow regulator can comprise a gas flow control mechanism, including a spring-loaded membrane bounding a gas-receiving chamber, which is subjected to the pressure of the input gas, and a flow-control valve connected to the membrane and a restrictor or constriction at the outlet of the gas flow regulator. The constriction and the force of the spring can be controllable.
For the regulation of the flow rate of liquids and gases a membrane flow regulator of this type is known, in which the outlet flow of an adjustable valve is controlled by an adjustable spring-loaded flexible membrane so that with increased fluid input the output cross section of the valve is reduced. This membrane bounds a space in which the fluid arrives through the adjustable valve and which is connected with a restrictor, through which the fluid flows.
One such regulator, for example, is taught in German utility model DE-GM No. 16 56 212, in which a reducing valve is provided as a restrictor, leading to a flow meter connected to it after the principal flow element and to the outflow side of the space over the membrane. With this additional mechanism the flow adjustment precision is improved.
A similar regulator is described in German patent document DE-OS No. 21 55 323, which to be sure has no flow meter. Another membrane flow regulator of the above type is described in German patent document DE-OS No. 23 34 348 in which a pressure surge is attenuated by a compensating member, particularly in the form of an attenuating piston, subjected to the inlet-side pressure and passing through the membrane.
Finally, in French patent document No. 23 49 084, a membrane flow regulator is taught, in which the spring acting on the membrane is formed as a kind of leaf spring and a plunger or push rod shaped connecting body engaged by the membrane acts on the regulating valve. On the outlet side a fine orifice is provided as a restrictor, after which a by-pass to the space adjacent the membrane branches off. This regulator is suitable for regulation of very slight flow rates in low pressure flows.
All these known regulators employed as gas flow meters presuppose gases, which do not change their composition during the regulating process, for example, do not condense out or have components which condense out since on the other hand the functioning of the regulating process would be disturbed by the condensate formed by the condensation process. Furthermore, because of the condensation irregular variation of undetermined components in the mixture could occur, which would be a particular problem for gas flows with nonuniform gas compositions.